In 3D, we rotate around axes (X, Y, Z). In 4D, we rotate in planes. With 4 dimensions, there are 6 possible rotation planes.

Three are familiar (3D rotations). Three are impossible in our world (4D rotations).

These rotations involve the W-axis. They're mathematically valid but physically impossible in our universe.

A tesseract contains 8 cubic cells - 3D "rooms" that share faces with each other in impossible ways. Each room you visit is one of these cells.

In 4D, a room can have more interior volume than its 3D exterior suggests. The "extra" space extends into the W dimension.

Think of it like this: a flat shadow of a box looks like a square - you can't tell how deep it is. Similarly, a 3D "shadow" of a 4D room hides its W-depth.

The portals connect cubic cells through their shared faces. When you step through a portal, you're moving in the W direction - even though it feels like you're walking forward.

This is why each room can lead to multiple others without overlapping. They're not stacked in 3D; they're arranged in 4D.

A 4D being looking at you would see your entire 3D body at once - your skin, your organs, your skeleton - all simultaneously visible, like how you can see the entire 2D cross-section of an orange slice.

Your timeline would appear as a 4D "worm" - every moment of your existence laid out like a sculpture through time.

Einstein showed that time is dimension-like. But the W-axis here is a fourth spatial dimension - not time. It's a direction you could theoretically walk in, if physics allowed it.

In this tesseract, you're exploring what it might feel like if that extra direction actually existed.

Your brain evolved in 3D. It has no hardware for processing 4D space directly. What you're seeing is your visual cortex's best attempt at interpreting something it was never designed to understand.

The confusion, the wrongness, the sense that something is off - that's your 3D brain brushing against a higher reality it cannot fully grasp.